[PATCH 0/4] input: Add new sun4i-lradc-keys driver

@@ -0,0 +1,20 @@
+Allwinner sun4i low res adc attached tablet keys
+------------------------------------------------
+
+Required properties:
+ - compatible: "allwinner,sun4i-lradc-keys"
+ - reg: mmio address range of the chip
+ - interrupts: interrupt to which the chip is connected
+ - allwinner,chan0-step: step in mV between keys must be 150 or 200
+ - allwinner,chan0-keycodes: array of include/uapi/linux/input.h KEY_ codes
+
+Example:
+
+	lradc: lradc@01c22800 {
+		compatible = "allwinner,sun4i-lradc-keys";
+		reg = <0x01c22800 0x100>;
+		interrupts = <31>;
+		allwinner,chan0-step = <200>;
+		/* KEY_VOLUMEUP VOLUMEDOWN MENU ENTER HOME */
+		allwinner,chan0-keycodes = <115 114 139 28 102>;
+	};

@@ -544,6 +544,16 @@ config KEYBOARD_STMPE
 	  To compile this driver as a module, choose M here: the module will be
 	  called stmpe-keypad.
 
+config KEYBOARD_SUN4I_LRADC
+	tristate "Allwinner sun4i low res adc attached tablet keys support"
+	depends on ARCH_SUNXI
+	help
+	  This selects support for the Allwinner low res adc attached tablet
+	  keys found on Allwinner sunxi SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sun4i-lradc-keys.
+
 config KEYBOARD_DAVINCI
 	tristate "TI DaVinci Key Scan"
 	depends on ARCH_DAVINCI_DM365

@@ -50,6 +50,7 @@ obj-$(CONFIG_KEYBOARD_SH_KEYSC)		+= sh_keysc.o
 obj-$(CONFIG_KEYBOARD_SPEAR)		+= spear-keyboard.o
 obj-$(CONFIG_KEYBOARD_STMPE)		+= stmpe-keypad.o
 obj-$(CONFIG_KEYBOARD_STOWAWAY)		+= stowaway.o
+obj-$(CONFIG_KEYBOARD_SUN4I_LRADC)	+= sun4i-lradc-keys.o
 obj-$(CONFIG_KEYBOARD_SUNKBD)		+= sunkbd.o
 obj-$(CONFIG_KEYBOARD_TC3589X)		+= tc3589x-keypad.o
 obj-$(CONFIG_KEYBOARD_TEGRA)		+= tegra-kbc.o

@@ -0,0 +1,243 @@
+/*
+ * Allwinner sun4i low res adc attached tablet keys driver
+ *
+ * Copyright (C) 2014 Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * Allwinnner sunxi SoCs have a lradc which is specifically designed to have
+ * various (tablet) keys (ie home, back, search, etc). attached to it using
+ * a resistor network. This driver is for the keys on such boards.
+ *
+ * There are 2 channels, currently this driver only supports chan0 since there
+ * are no boards known to use chan1. The devicetree properties are already
+ * prefixed with chan0 as preparation for chan1 support in the future.
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#define LRADC_CTRL		0x00
+#define LRADC_INTC		0x04
+#define LRADC_INTS		0x08
+#define LRADC_DATA0		0x0c
+#define LRADC_DATA1		0x10
+
+/* LRADC_CTRL bits */
+#define FIRST_CONVERT_DLY(x)	((x) << 24) /* 8 bits */
+#define CHAN_SELECT(x)		((x) << 22) /* 2 bits */
+#define CONTINUE_TIME_SEL(x)	((x) << 16) /* 4 bits */
+#define KEY_MODE_SEL(x)		((x) << 12) /* 2 bits */
+#define LEVELA_B_CNT(x)		((x) << 8)  /* 4 bits */
+#define HOLD_EN(x)		((x) << 6)
+#define LEVELB_VOL(x)		((x) << 4)  /* 2 bits */
+#define SAMPLE_RATE(x)		((x) << 2)  /* 2 bits */
+#define ENABLE(x)		((x) << 0)
+
+/* LRADC_INTC and LRADC_INTS bits */
+#define CHAN1_KEYUP_IRQ		BIT(12)
+#define CHAN1_ALRDY_HOLD_IRQ	BIT(11)
+#define CHAN1_HOLD_IRQ		BIT(10)
+#define	CHAN1_KEYDOWN_IRQ	BIT(9)
+#define CHAN1_DATA_IRQ		BIT(8)
+#define CHAN0_KEYUP_IRQ		BIT(4)
+#define CHAN0_ALRDY_HOLD_IRQ	BIT(3)
+#define CHAN0_HOLD_IRQ		BIT(2)
+#define	CHAN0_KEYDOWN_IRQ	BIT(1)
+#define CHAN0_DATA_IRQ		BIT(0)
+
+#define MAX_KEYS		13
+
+/* Lookup table to map the adc val to a keycode index for 150 mv step size */
+static const u8 adc_val_to_key_index_step150[64] = {
+	0, 0, 0,
+	1, 1, 1, 1, 1,
+	2, 2, 2, 2, 2,
+	3, 3, 3, 3,
+	4, 4, 4, 4, 4,
+	5, 5, 5, 5, 5,
+	6, 6, 6, 6, 6,
+	7, 7, 7, 7,
+	8, 8, 8, 8, 8,
+	9, 9, 9, 9, 9,
+	10, 10, 10, 10,
+	11, 11, 11, 11,
+	12, 12, 12, 12, 12, 12, 12, 12, 12, 12
+};
+
+/* Lookup table to map the adc val to a keycode index for 200 mv step size */
+static const u8 adc_val_to_key_index_step200[64] = {
+	0, 0, 0, 0, 0, 0, 0, 0,
+	1, 1, 1, 1, 1, 1, 1,
+	2, 2, 2, 2, 2, 2, 2,
+	3, 3, 3, 3, 3, 3,
+	4, 4, 4, 4, 4, 4,
+	5, 5, 5, 5, 5, 5,
+	6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+	7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
+};
+
+struct sun4i_lradc_data {
+	struct device *dev;
+	struct input_dev *input;
+	void __iomem *base;
+	u32 chan0_step;
+	u32 chan0_keycode;
+	u32 chan0_keycodes[MAX_KEYS];
+};
+
+static irqreturn_t sun4i_lradc_irq(int irq, void *dev_id)
+{
+	struct sun4i_lradc_data *lradc = dev_id;
+	u32 ints, val;
+
+	ints  = readl(lradc->base + LRADC_INTS);
+
+	/*
+	 * lradc supports only one keypress at a time, release does not give
+	 * any info as to which key was released, so we cache the keycode.
+	 */
+	if ((ints & CHAN0_KEYDOWN_IRQ) && lradc->chan0_keycode == 0) {
+		val = readl(lradc->base + LRADC_DATA0);
+		if (lradc->chan0_step == 150)
+			val = adc_val_to_key_index_step150[val];
+		else
+			val = adc_val_to_key_index_step200[val];
+
+		lradc->chan0_keycode = lradc->chan0_keycodes[val];
+		input_report_key(lradc->input, lradc->chan0_keycode, 1);
+	}
+
+	if (ints & CHAN0_KEYUP_IRQ) {
+		input_report_key(lradc->input, lradc->chan0_keycode, 0);
+		lradc->chan0_keycode = 0;
+	}
+
+	input_sync(lradc->input);
+
+	writel(ints, lradc->base + LRADC_INTS);
+
+	return IRQ_HANDLED;
+}
+
+static int sun4i_lradc_open(struct input_dev *dev)
+{
+	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
+
+	/*
+	 * Set sample time to 16 ms / 62.5 Hz. Wait 2 * 16 ms for key to
+	 * stabilize on press, wait (1 + 1) * 16 ms for key release
+	 */
+	writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
+		SAMPLE_RATE(2) | ENABLE(1), lradc->base + LRADC_CTRL);
+
+	writel(CHAN0_KEYUP_IRQ | CHAN0_KEYDOWN_IRQ, lradc->base + LRADC_INTC);
+
+	return 0;
+}
+
+static void sun4i_lradc_close(struct input_dev *dev)
+{
+	struct sun4i_lradc_data *lradc = input_get_drvdata(dev);
+
+	/* Disable lradc, leave other settings unchanged */
+	writel(FIRST_CONVERT_DLY(2) | LEVELA_B_CNT(1) | HOLD_EN(1) |
+		SAMPLE_RATE(2), lradc->base + LRADC_CTRL);
+	writel(0, lradc->base + LRADC_INTC);
+}
+
+static int sun4i_lradc_probe(struct platform_device *pdev)
+{
+	struct sun4i_lradc_data *lradc;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int i, ret;
+
+	lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
+	if (!lradc)
+		return -ENOMEM;
+
+	ret = of_property_read_u32(np, "allwinner,chan0-step",
+				   &lradc->chan0_step);
+	if (ret || (lradc->chan0_step != 150 && lradc->chan0_step != 200)) {
+		dev_err(dev, "Invalid allwinner,chan0-step dt-property\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < MAX_KEYS; i++)
+		of_property_read_u32_index(np, "allwinner,chan0-keycodes",
+					   i, &lradc->chan0_keycodes[i]);
+
+	lradc->dev = dev;
+	lradc->input = devm_input_allocate_device(dev);
+	if (!lradc->input)
+		return -ENOMEM;
+
+	lradc->input->name = pdev->name;
+	lradc->input->phys = "sun4i_lradc/input0";
+	lradc->input->open = sun4i_lradc_open;
+	lradc->input->close = sun4i_lradc_close;
+	lradc->input->id.bustype = BUS_HOST;
+	lradc->input->id.vendor = 0x0001;
+	lradc->input->id.product = 0x0001;
+	lradc->input->id.version = 0x0100;
+	lradc->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY);
+	for (i = 0; i < MAX_KEYS; i++)
+		set_bit(lradc->chan0_keycodes[i], lradc->input->keybit);
+	input_set_drvdata(lradc->input, lradc);
+
+	lradc->base = devm_ioremap_resource(dev,
+			      platform_get_resource(pdev, IORESOURCE_MEM, 0));
+	if (IS_ERR(lradc->base))
+		return PTR_ERR(lradc->base);
+
+	ret = devm_request_irq(dev, platform_get_irq(pdev, 0), sun4i_lradc_irq,
+			       0, "sun4i-lradc-keys", lradc);
+	if (ret)
+		return ret;
+
+	ret = input_register_device(lradc->input);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, lradc);
+	return 0;
+}
+
+static const struct of_device_id sun4i_lradc_of_match[] = {
+	{ .compatible = "allwinner,sun4i-lradc-keys", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sun4i_lradc_of_match);
+
+static struct platform_driver sun4i_lradc_driver = {
+	.driver = {
+		.owner	= THIS_MODULE,
+		.name	= "sun4i-lradc-keys",
+		.of_match_table = of_match_ptr(sun4i_lradc_of_match),
+	},
+	.probe	= sun4i_lradc_probe,
+};
+
+module_platform_driver(sun4i_lradc_driver);
+
+MODULE_DESCRIPTION("Allwinner sun4i low res adc attached tablet keys driver");
+MODULE_AUTHOR("Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>");
+MODULE_LICENSE("GPL");

@@ -447,6 +447,13 @@
 			interrupts = <24>;
 		};
 
+		lradc: lradc@01c22800 {
+			compatible = "allwinner,sun4i-lradc-keys";
+			reg = <0x01c22800 0x100>;
+			interrupts = <31>;
+			status = "disabled";
+		};
+
 		sid: eeprom@01c23800 {
 			compatible = "allwinner,sun4i-sid";
 			reg = <0x01c23800 0x10>;

@@ -75,6 +75,13 @@
 			};
 		};
 
+		lradc: lradc@01c22800 {
+			allwinner,chan0-step = <200>;
+			/* KEY_VOLUMEUP VOLUMEDOWN MENU ENTER HOME */
+			allwinner,chan0-keycodes = <115 114 139 28 102>;
+			status = "okay";
+		};
+
 		uart0: serial@01c28000 {
 			pinctrl-names = "default";
 			pinctrl-0 = <&uart0_pins_a>;

@@ -404,6 +404,13 @@
 			reg = <0x01c20c90 0x10>;
 		};
 
+		lradc: lradc@01c22800 {
+			compatible = "allwinner,sun4i-lradc-keys";
+			reg = <0x01c22800 0x100>;
+			interrupts = <31>;
+			status = "disabled";
+		};
+
 		sid: eeprom@01c23800 {
 			compatible = "allwinner,sun4i-sid";
 			reg = <0x01c23800 0x10>;

@@ -55,6 +55,13 @@
 			};
 		};
 
+		lradc: lradc@01c22800 {
+			allwinner,chan0-step = <200>;
+			/* KEY_VOLUMEUP VOLUMEDOWN MENU ENTER HOME */
+			allwinner,chan0-keycodes = <115 114 139 28 102>;
+			status = "okay";
+		};
+
 		uart1: serial@01c28400 {
 			pinctrl-names = "default";
 			pinctrl-0 = <&uart1_pins_b>;

@@ -362,6 +362,13 @@
 			reg = <0x01c20c90 0x10>;
 		};
 
+		lradc: lradc@01c22800 {
+			compatible = "allwinner,sun4i-lradc-keys";
+			reg = <0x01c22800 0x100>;
+			interrupts = <31>;
+			status = "disabled";
+		};
+
 		sid: eeprom@01c23800 {
 			compatible = "allwinner,sun4i-sid";
 			reg = <0x01c23800 0x10>;

@@ -86,6 +86,13 @@
 			};
 		};
 
+		lradc: lradc@01c22800 {
+			allwinner,chan0-step = <200>;
+			/* VOLUMEUP VOLUMEDOWN MENU SEARCH HOME ESC ENTER */
+			allwinner,chan0-keycodes = <115 114 139 217 102 1 28>;
+			status = "okay";
+		};
+
 		uart0: serial@01c28000 {
 			pinctrl-names = "default";
 			pinctrl-0 = <&uart0_pins_a>;

@@ -531,6 +531,13 @@
 			interrupts = <0 24 1>;
 		};
 
+		lradc: lradc@01c22800 {
+			compatible = "allwinner,sun4i-lradc-keys";
+			reg = <0x01c22800 0x100>;
+			interrupts = <0 31 4>;
+			status = "disabled";
+		};
+
 		sid: eeprom@01c23800 {
 			compatible = "allwinner,sun7i-a20-sid";
 			reg = <0x01c23800 0x200>;